Set-up - IE8, Windows 2008R2

Hi

I have a number of sites listed as Trusted because of the use of NTLM authentication for Intranet sites. However, when I move from a non-trusted site to a link to a trusted site with IE8 I keep on getting a pop-up asking if I am sure.

Where in group policies can I switch off this annoying pop-up?

thanks

J.